The present invention relates to a cartridge and an electrophotographic image forming apparatus to which the cartridge is detachably mountable.
The present invention is suitably used with developing means for developing an electrostatic latent image formed on an electrophotographic photosensitive member into a visualized image (toner image), a rotary type developing device in which a plurality of cartridge type developing devices (developing cartridges) are carried on a rotary, a developing cartridge detachably mountable to such a developing device, and an electrophotographic image forming apparatus provided with such a developing device. The present invention is particularly suitable for a color electrophotographic image forming apparatus.
Here, the electrophotographic image forming apparatus is an apparatus for forming an image on a recording material through an electrophotographic image forming process. For example, it is an electrophotographic copying machine, an electrophotographic printer (LED printer, laser beam printer), an electrophotographic printer type facsimile machine, an electrophotographic printer type word processor and the like.
It is known that a developing member for developing an electrostatic latent image on the electrophotographic photosensitive member and a toner accommodating portion for accommodating a developer (toner) are unified by a cartridge frame into a cartridge which is detachably mountable to the main assembly of the image forming apparatus (developing cartridge type).
Also, a process cartridge type is known in which an electrophotographic photosensitive member and process means actable on the electrophotographic photosensitive member are unified into a cartridge which is detachably mountable to the main assembly of the image forming apparatus.
According to such a cartridge type, the operationality can be remarkably improved because the maintenance operation of the apparatus can be carried out in effect by the user without a serviceman. Therefore, the cartridge type is widely used in the image forming apparatus.
The cartridge contains developing means for applying toner to the latent image formed on the photosensitive drum. The developing means comprises a developing roller functioning as a developing member for feeding the toner to the photosensitive drum, a toner supplying roller functioning as a developer application member for supplying the toner onto the developing roller, a developing blade functioning as a developer amount regulating member for regulating an amount of the developer on the developing roller and so on. Such members a unified with a toner frame which accommodates the toner and which is supported on a developing device frame, so that a cartridge frame is constituted.
In an apparatus which forms an image through the electrophotographic type process, a photosensitive drum uniformly charged by a charging device is selectively exposed to light to form an electrostatic latent image, and the electrostatic latent image is visualized with the toner by the developing means. The toner image is then transferred onto a recording material.
In order to apply a predetermined bias voltage to the toner, the developing roller has to be supplied with a predetermined bias voltage.
Heretofore, a developing bias electrical contact provided on a longitudinal end surface of the cartridge or a developing bias contact provided on the bottom surface of the cartridge contact the developing bias contact provided in the main assembly of the image forming apparatus. The present invention provides a further development of such art.
Accordingly, it is a principal object of the present invention to provide a cartridge and an electrophotographic image forming apparatus the cartridge having mounting and demounting operability relative to the main assembly of the apparatus.
It is another object of the present invention to provide a cartridge and an electrophotographic image forming apparatus wherein the electrical connection between the electric contacts of the main assembly and the cartridge can be assuredly established when the cartridge is mounted to the main assembly of the electrophotographic image forming apparatus in place.
It is a further object of the present invention to provide a cartridge and an electrophotographic image forming apparatus wherein when the cartridge is mounted to the main assembly of the electrophotographic image forming apparatus, the relative positional accuracy between the electrical contact of the cartridge and the electrical contact of the main assembly of the apparatus is improved.
It is a further object of the present invention to provide a cartridge and an electrophotographic image forming apparatus wherein when the cartridge is mounted to the main assembly of the electrophotographic image forming apparatus, the contact pressure between the electrical contact of the cartridge and the electrical contact of the main assembly of the apparatus is improved. It is a further object of the present invention to provide a cartridge and an electrophotographic image forming apparatus wherein an electrical contact is provided on a guide for guiding a cartridge when the cartridge is mounted to the main assembly of the electrophotographic image forming apparatus.
It is a further object of the present invention to provide a cartridge and an electrophotographic image forming apparatus wherein the distance between a developing bias contact of the main assembly of the image forming apparatus and a developing bias contact of the cartridge is maintained constant to assure a constant contact pressure while improving the operability.